Weeks 16 to 20 of Your Pregnancy

Weeks 16 to 20 of Your Pregnancy

Around your 18th week, your baby will be about 8 inches long and weigh about 8 ounces. You will start to "show," so that you look pregnant to people around you. You may also notice some changes in your skin, such as itchy spots on your palms or acne on your face.

During weeks 16 to 20, your umbilical cord grows and gets thicker. This is the cord that carries blood and food from you to your baby. Your baby is now able to pass urine, and your baby's first stool (meconium) is starting to collect in its intestines. Hair is also beginning to grow on your baby's head.

Sometime between 18 and 22 weeks, you will start to feel your baby move. At first, these small fetal movements feel like fluttering or “butterflies.” Some women say that they feel like gas bubbles. As the baby grows, these movements will become stronger.

You will also be having an ultrasound around 18 to 20 weeks in the radiology department. At that time, we will be checking the baby's development. The ultrasound is safe and uses sound waves to create an image of the baby. In order to provide you with a wonderful experience, please click here to see some general guidelines.

As your pregnancy moves along, it is common to worry or feel anxious. Your body is changing a lot. And you are thinking about giving birth, the health of your baby, and becoming a parent. You can learn to cope with any anxiety and stress you feel. This care sheet provides stress reduction techniques that can help you during pregnancy and in the years to come.

Exercise is one way to reduce stress. It can also give you energy and help you stay at your best weight. Exercise is also great for sleeping well, fighting constipation, and preparing you for labor and delivery. Most women can exercise right up to delivery. Talk to your doctor about what type and how much exercise to do at each stage of your pregnancy.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It’s also a good idea to know your test results and keep a list of the medicines you take.

How can you care for yourself at home?

Reduce stress

  • Ask for help with cooking and housekeeping.
  • Figure out who or what causes your stress. Avoid these people or situations as much as possible.
  • Relax every day. Taking 10- to 15-minute breaks can make a big difference. Take a walk, listen to music, or take a warm bath.
  • Learn relaxation techniques at prenatal or yoga class. Or buy a relaxation tape.
  • List your fears about having a baby and becoming a parent. Share the list with someone you trust. Decide which worries are really small, and try to let them go.


  • If you did not exercise much before pregnancy, start slowly. Walking is best. Pace yourself, and do a little more every day.
  • Brisk walking, easy jogging, low-impact aerobics, water aerobics, and yoga are good choices. Some sports, such as scuba diving, horseback riding, downhill skiing, gymnastics, and water skiing, are not a good idea.
  • Do not exercise more than 45 minutes. Limit high-intensity exercise to 10 to 15 minutes and moderate exercise to 20 to 30 minutes. Keep your heart rate below 140 beats per minute so you do not overheat.
  • Wear loose clothing, good shoes, and a good bra.
  • Warm up and cool down to start and finish your exercise.
  • Avoid deep bending and intense stretches.
  • If you want to use weights, be sure to use light weights. They reduce stress on your joints.

Stay at the best weight for you

  • Experts recommend that you gain about 1 pound a month during the first 3 months of your pregnancy.
  • Experts recommend that you gain about 1 pound a week during your last 6 months of pregnancy, for a total weight gain of 25 to 30 pounds.
  • If you are underweight, you will need to gain more weight (about 28 to 40 pounds).
  • If you are overweight, you may not need to gain as much weight (about 15 to 25 pounds).
  • If you are gaining weight too fast, use common sense. Exercise every day, and limit sweets, fast foods, and fats. Choose lean meats, fruits, and vegetables.
  • If you are having twins or more, your doctor may refer you to a dietitian.

Be aware of normal skin changes

  • During this time, your uterus is expanding beyond your belly button and causing your belly to stretch. This can lead to reddish lines called stretch marks on your belly. Stretch marks can also appear on other parts of your changing body, such as your breasts, buttocks, and thighs. After the birth, most stretch marks fade to nearly invisible silvery lines.
  • Many women get a darkening line from their belly button to their pubic bone. This line is called "linea nigra." It will gradually disappear in the months after delivery.
  • Pregnancy hormones may cause brown patches on your nose, forehead, cheeks, and neck. This is called the “mask of pregnancy." These spots will lighten and disappear after pregnancy. During pregnancy, use sunscreen to prevent the spots from getting darker and to protect your skin from sunburn.
  • You may also get red spots on your face, neck, upper chest, arms, or the palms of your hands. These are caused by pregnancy hormones and will also disappear after the birth.
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